sodium tetrahydroborate; nickel dichloride in methanol T=20°C; 3 h;

1: With pyridine; ethylene dibromide; niobium bromide; tetrabutylammomium bromide; tetra-(n-butyl)ammonium iodide in N,N-dimethyl-formamide T=80°C; Electrochemical reaction; 2: With hydrogenchloride in N,N-dimethyl-formamide